The present invention relates to fluid-film bearings for rotating machinery and more particularly to bearings which include unique resilient load-supporting foil bearing insert assemblies.
Hydrodynamic bearings are well known and have been used effectively as supports for rotating machinery, including high speed applications. The term hydrodynamic bearing, as used herein, defines that class of fluid-film bearings which has its surfaces separated by a thin layer of either liquid or gas, the film being established and the pressure generated therein by the relative motion between the bearing surfaces. This is distinguished from bearings of the hydrostatic type which require feed of pressurized fluid from an external source.
Although many past hydrodynamic bearings have been rigid and rigidly mounted and thus not self-aligning unless provided with complex, expensive and frequently troublesome gimbal and pivot supports, recent advances have resulted in compliant hydrodynamic bearings equipped with foil-insert assemblies designed to generate lubricating films and to support loads.
Some, such as those shown in U.S. Pat. Nos. 3,375,046; 3,382,014 and 4,082,375 may employ a plurality of bearing foils and some, such as those shown in U.S. Pat. Nos. 3,747,997 and 3,809,443 may use a unitary solid bearing foil. In U.S. Pat. No. 3,635,534, both types are disclosed. All, however, rely on the hydrodynamic formation of a plurality of lubricating fluid wedges which, due to side leakage and an inability to uniformly replenish the fluid thus lost, lose film thickness.